Title of Invention	"A PROCESS FOR PRODUCING USABLE SUBSTANCES IN A COST EFFECTIVE WAY FROM WASTE ACID SLUDGE GENERATED IN ACID WASHING OF CRUDE BENZOL"
Abstract	The invention provides a process of producing unsable substances in a cost effective way from waste acid sludge generated in acid washing of crude benzol, comprising the following steps : (a) mixing the waste acid sludge and a saturated ammonium sulphate solution in water; (b) allowing dissipation of the heat generated in the mixture produced in step (a) and cooling of the mixture to room temperature; (c) settling the mixture obtained in step (b),to allow sulphuric acidic solution (acid cone. 20-25% W/W) to be at the bottom layer and muck of organic matters containing sulphuric acid (acid cone. 7-8% W/W) at the top layer; (d) draining out the bottom layer, and retaining the top layer of the mixture settled in step (c); (e) diluting the top layer of step (d) with tar/ anthracene/heavy oil, neutralising the mixture thus produced with sodium hydroxide solution, and transferring the neutralised mixture to tar distillation plant for use as fuel in the form of pitch creosote mixture (PCM); (f) extracting the bottom layer of step (d) with phenol fraction of boiling point 150-205°C, obtained in the distillation of tar to get regenerated acid (acid cone. 20-25% W/W), as a bottom product of extraction on settling and sending the same to ammonium sulphate plant for use there; (g) collecting the top layer of acidic saturated solvent (acid cone. 1-1.2%W/W) on settling, as top product of extraction in step (f); (h) neutralising the top product of extraction in step (g) with sodium phenolate solution, recovering the solvent therein by distillation, and recycling the regenerated solvent to step (f); and (1) mixing the residue of distillation in step (h) with tar/anthracene/heavy oil, and transferring the mixture to tar distillation plant for use as fuel in the form of PCM.

Title of Invention

"A PROCESS FOR PRODUCING USABLE SUBSTANCES IN A COST EFFECTIVE WAY FROM WASTE ACID SLUDGE GENERATED IN ACID WASHING OF CRUDE BENZOL"

Abstract

The invention provides a process of producing unsable substances in a cost effective way from waste acid sludge generated in acid washing of crude benzol, comprising the following steps : (a) mixing the waste acid sludge and a saturated ammonium sulphate solution in water; (b) allowing dissipation of the heat generated in the mixture produced in step (a) and cooling of the mixture to room temperature; (c) settling the mixture obtained in step (b),to allow sulphuric acidic solution (acid cone. 20-25% W/W) to be at the bottom layer and muck of organic matters containing sulphuric acid (acid cone. 7-8% W/W) at the top layer; (d) draining out the bottom layer, and retaining the top layer of the mixture settled in step (c); (e) diluting the top layer of step (d) with tar/ anthracene/heavy oil, neutralising the mixture thus produced with sodium hydroxide solution, and transferring the neutralised mixture to tar distillation plant for use as fuel in the form of pitch creosote mixture (PCM); (f) extracting the bottom layer of step (d) with phenol fraction of boiling point 150-205°C, obtained in the distillation of tar to get regenerated acid (acid cone. 20-25% W/W), as a bottom product of extraction on settling and sending the same to ammonium sulphate plant for use there; (g) collecting the top layer of acidic saturated solvent (acid cone. 1-1.2%W/W) on settling, as top product of extraction in step (f); (h) neutralising the top product of extraction in step (g) with sodium phenolate solution, recovering the solvent therein by distillation, and recycling the regenerated solvent to step (f); and (1) mixing the residue of distillation in step (h) with tar/anthracene/heavy oil, and transferring the mixture to tar distillation plant for use as fuel in the form of PCM.

Full Text	The present invention relates to a process of producing usable substances in a cost effective way from waste acid sludge generated in acid washing of crude benzol. The invention relates more particularly to a process for producing sulphuric acid of 20-25%concentration for use in ammonium sulphate plants and muck of organic residue for use as fuel in tar distillation plants in the form of pitch creosote mixture (PCM). A benzol rectification plant produces benzene, toluene and xylene (BTX) which is stripped of CS2 impurity in defronting column and subjected to batch acid washing in a number of stages with 98% cone, sulphuric acid to remove thiopheneC4H4S) through polymerisation and co-polymerisation reaction with unsaturated compounds and organic matters present in BTX, with generation of an acid sludge which is a mixture of products of said polymerisation and co-polymerisation reactions. At present no suitable process is available for producing usable substances like sulphuric acid, acid muck of tar and organic residue in a cost-effective way from the waste acid sludge, and utilising the same commercially in ammonium sulphate and tar distillation plants. So the acid sludge is now disposed of as a waste material causing pollution of environment. The object of the invention is to provide a simple and cost effective process for commercially utilising the acid sludge generated in the benzol rectification plants. The other object is to prevent pollution of environment caused by disposal of the acid sludge as a waste material. The composition of the acid sludge varies depending on the quality of the feed stock used and processing parameters followed in benzol rectification plants. A typical composition of the acid sludge which is a black viscous mass is given in Table I. The invented process comprises basically the following steps : (a) solution preparation, (b) solvent extraction, (c) solvent neutralization and (d) solvent regeneration. The invented process comprises the following steps :- (a) mixing the waste acid sludge and a saturated solution of ammonium sulphate in water in a preferred ratio of 1:3 (V/V); (b) allowing dissipation of the heat of dilution generated in the mixture produced in step (a) and cooling of the mixture to room temperature; (c) settling the mixture obtained in step (b), to allow sulphuric acidic solution (acid conc. 20-25% W/W) to be at the bottom layer and muck of organic matters containing sulphuric acid (acid cone. 7-8% W/W) at the top layer, for a preferred period of 2k hours; (d) draining out the bottom layer, and retaining the top layer of the mixture settled in step (c); (e) diluting the top layer of step (d) with tar/anthracene/ heavy oil in the preferred,mixture to oil,ratio of 1:3 W/W, neutralising the acid content of mixture thus produced with sodium hydroxide solution, and transferring the neutralised mixture to tar distillation plant for use as pitch creosote mixture fuel (PCM); (f) extracting the bottom layer of step (d) with phenol fraction of boiling point 150-200°C, obtained in the distillation of tar, in the preferred,mixture to phenol,ratio of 1:3 (V/V), to get regenerated acid (acid cone. 20-25%W/W) as a bottom product of extraction on settling, and sending the same to ammonium sulphate plant for use there; (g) collecting the top layer of acidic saturated solvent (acid cone. 1-1.2%W/W) on settling as top product of extraction in step (f); (h) neutralising the top product of extraction in step (g) with sodium phenolate solution, recovering the solvent therein by distillation, and recycling the regenerated solvent to step (f); and (i) mixing the residue of distillation in step (h) with tar/ anthracene/heavy oil, and transferring the mixture to tar distillation plant for use as fuel in the form of PCM. The invented process has the following advantages :- 1. It provides a simple and cost effective method of utilising the usuable substances in the waste acid sludge generated in acid washing of crude benzol. 2. It prevents pollution of environment caused by disposal of the acid sludge as a waste material. 3. It provides a high yield of sulphuric acid (acid cone. 20-25% W/W) and PCM fuel. 4. It provides a supply of a clean sulphuric acid to ammonium sulphate plant for producing ammonium sulphate crystals of improved colour. Table I Typical composition of Waste Acid Sludge Generated in Acid Washing of Crude Benzol. (Table Removed) Claim :- 1. A process of producing usable substances in a cost from waste acid sludge generated in acid washing of crude benzol, comprising the following steps : (a) mixing the waste acid sludge and a saturated ammonium sulphate solution in water; (b) allowing dissipation of the heat generated in the mixture produced in step (a) and cooling of the mixture to room temperature; (c) settling the mixture obtained in step (b), to allow sulphuric acidic solution (acid cone. 20-25%W/W) to be at the bottom layer and muck of organic matters containing sulphuric acid (acid cone. 7-8% W/W) at the top layer; (d) draining out the bottom layer, and retaining the top layer of the mixture settled in step (c); (e) diluting the top layer of step (d) with tar/anthracene/heavy oil, neutralising the mixture thus produced with sodium hydroxide solution, and transferring the neutralised mixture to tar distillation plant for use as fuel in the form of pitch creosote mixture (PCM); (f) extracting the bottom layer of step (d) with phenol fraction of boiling point 150-205°C, obtained in the distillation of tar to get regenerated acid (acid cone. 20-2596 W/W), as a bottom product of extraction on settling and sending the same to ammonium sulphate plant for use there; (g) collecting the top layer of acidic saturated solvent (acid cone. 1-1.2 W/W) on settling, as top product of extraction in step (f); (h) neutralising the top product of extraction in step (g) with sodium phenolate solution, recovering the solvent therein by distillation, and recycling the regenerated solvent to step (f); and (i) mixing the residue of distillation in step (h) with tar/anthracene/heavy oil, and transferring the mixture to tar distillation plant for use as fuel in the form of PCM. 2. The process as claimed in claim 1, wherein in step (a) waste acid sludge and saturated ammonium sulphate solution are mixed in the ratio of 1:3 (V/V). 3. The process as claimed in claim 1, wherein the mixture obtained in step (b) is allowed to settle in step (c) for 2k hours. 4. The process as claimed in claim 1, wherein in step (e), the top layer of step (d) is diluted with tar/anthracene/heavy oil in the,mixture to oil, ratio of 1:3 W/W. 5. The process as claimed in claim 1, wherein in step (f) the bottom layer is extracted with phenol fraction of boiling point 150-205°C in the, mixture to phenol,ratio of 1:3 (V/V).

Full Text

The present invention relates to a process of producing usable substances in a cost effective way from waste acid sludge generated in acid washing of crude benzol. The invention relates more particularly to a process for producing sulphuric acid of 20-25%concentration for use in ammonium sulphate plants and muck of organic residue for use as fuel in tar distillation plants in the form of pitch creosote mixture (PCM).
A benzol rectification plant produces benzene, toluene and xylene (BTX) which is stripped of CS2 impurity in defronting column and subjected to batch acid washing in a number of stages with 98% cone, sulphuric acid to remove thiopheneC4H4S) through polymerisation and co-polymerisation reaction with unsaturated compounds and organic matters present in BTX, with generation of an acid sludge which is a mixture of products of said polymerisation and co-polymerisation reactions.
At present no suitable process is available for producing usable substances like sulphuric acid, acid muck of tar and organic residue in a cost-effective way from the waste acid sludge, and utilising the same commercially in ammonium sulphate and tar distillation plants. So the acid sludge is now disposed of as a waste material causing pollution of environment.
The object of the invention is to provide a simple and cost effective process for commercially utilising the acid sludge generated in the benzol rectification plants.
The other object is to prevent pollution of environment caused by disposal of the acid sludge as a waste material.
The composition of the acid sludge varies depending on the quality of the feed stock used and processing parameters followed in benzol rectification plants. A typical composition of the acid sludge which is a black viscous mass is given in Table I.
The invented process comprises basically the following steps : (a) solution preparation, (b) solvent extraction, (c) solvent neutralization and (d) solvent regeneration.
The invented process comprises the following steps :-
(a) mixing the waste acid sludge and a saturated solution
of ammonium sulphate in water in a preferred ratio of 1:3
(V/V);
(b) allowing dissipation of the heat of dilution generated
in the mixture produced in step (a) and cooling of the mixture
to room temperature;
(c) settling the mixture obtained in step (b), to allow
sulphuric acidic solution (acid conc. 20-25% W/W) to be at the
bottom layer and muck of organic matters containing sulphuric
acid (acid cone. 7-8% W/W) at the top layer, for a preferred
period of 2k hours;
(d) draining out the bottom layer, and retaining the top layer
of the mixture settled in step (c);
(e) diluting the top layer of step (d) with tar/anthracene/
heavy oil in the preferred,mixture to oil,ratio of 1:3 W/W,
neutralising the acid content of mixture thus produced with
sodium hydroxide solution, and transferring the neutralised
mixture to tar distillation plant for use as pitch creosote
mixture fuel (PCM);
(f) extracting the bottom layer of step (d) with phenol
fraction of boiling point 150-200°C, obtained in the distillation
of tar, in the preferred,mixture to phenol,ratio of 1:3 (V/V),
to get regenerated acid (acid cone. 20-25%W/W) as a bottom product of extraction on settling, and sending the same to ammonium sulphate plant for use there;
(g) collecting the top layer of acidic saturated solvent
(acid cone. 1-1.2%W/W) on settling as top product of extraction
in step (f);
(h) neutralising the top product of extraction in step (g) with sodium phenolate solution, recovering the solvent therein by distillation, and recycling the regenerated solvent to step (f); and
(i) mixing the residue of distillation in step (h) with tar/ anthracene/heavy oil, and transferring the mixture to tar distillation plant for use as fuel in the form of PCM.
The invented process has the following advantages :-
1. It provides a simple and cost effective method of
utilising the usuable substances in the waste acid sludge
generated in acid washing of crude benzol.
2. It prevents pollution of environment caused by disposal
of the acid sludge as a waste material.
3. It provides a high yield of sulphuric acid (acid cone.
20-25% W/W) and PCM fuel.
4. It provides a supply of a clean sulphuric acid to ammonium
sulphate plant for producing ammonium sulphate crystals of improved colour.
Table I
Typical composition of Waste Acid Sludge Generated in Acid Washing of Crude Benzol.
(Table Removed)

Claim :-
1. A process of producing usable substances in a cost
from waste acid sludge generated in acid washing of crude benzol, comprising the following steps : (a) mixing the waste acid sludge and a saturated ammonium sulphate solution in water; (b) allowing dissipation of the heat generated in the mixture produced in step (a) and cooling of the mixture to room temperature; (c) settling the mixture obtained in step (b), to allow sulphuric acidic solution (acid cone. 20-25%W/W) to be at the bottom layer and muck of organic matters containing sulphuric acid (acid cone. 7-8% W/W) at the top layer; (d) draining out the bottom layer, and retaining the top layer of the mixture settled in step (c); (e) diluting the top layer of step (d) with tar/anthracene/heavy oil, neutralising the mixture thus produced with sodium hydroxide solution, and transferring the neutralised mixture to tar distillation plant for use as fuel in the form of pitch creosote mixture (PCM); (f) extracting the bottom layer of step (d) with phenol fraction of boiling point 150-205°C, obtained in the distillation of tar to get regenerated acid (acid cone. 20-2596 W/W), as a bottom product of extraction on settling and sending the same to ammonium sulphate plant for use there; (g) collecting the top layer of acidic saturated solvent (acid cone. 1-1.2 W/W) on settling, as top product of extraction in step (f); (h) neutralising the top product of extraction in step (g) with sodium phenolate solution, recovering the solvent therein by distillation, and recycling the regenerated
solvent to step (f); and (i) mixing the residue of distillation in step (h) with tar/anthracene/heavy oil, and transferring the mixture to tar distillation plant for use as fuel in the form of
PCM.
2. The process as claimed in claim 1, wherein in step (a)
waste acid sludge and saturated ammonium sulphate solution are
mixed in the ratio of 1:3 (V/V).
3. The process as claimed in claim 1, wherein the mixture
obtained in step (b) is allowed to settle in step (c) for
2k hours.
4. The process as claimed in claim 1, wherein in step (e), the top layer of step (d) is diluted with tar/anthracene/heavy oil in the,mixture to oil, ratio of 1:3 W/W.
5. The process as claimed in claim 1, wherein in step (f) the bottom layer is extracted with phenol fraction of boiling point 150-205°C in the, mixture to phenol,ratio of 1:3 (V/V).

Documents:

892-del-1997-abstract.pdf

892-del-1997-claims.pdf

892-del-1997-correspondence-others.pdf

892-del-1997-correspondence-po.pdf

892-del-1997-description (complete).pdf

892-del-1997-form-1.pdf

892-del-1997-form-19.pdf

892-del-1997-form-2.pdf

892-del-1997-form-4.pdf

892-del-1997-gpa.pdf

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Patent Number

232036

Indian Patent Application Number

892/DEL/1997

PG Journal Number

13/2009

Publication Date

27-Mar-2009

Grant Date

15-Mar-2009

Date of Filing

08-Apr-1997

Name of Patentee

STEEL AUTHORITY OF INDIA LIMITED

Applicant Address

ISPAT BHAWAN, LODI ROAD, NEW DELHI-110003

Inventors:

#	Inventor's Name	Inventor's Address
1	TILAKRAJ BHASKARRAO CHAHANDE	RDCIS BHILAI CENTRE
2	SUSHIL KUMAR JAIN	CORPORATE OFFICE, SAIL, NEW DELHI
3	RAM PRASHAD SHARMA	RDCIS ROURKELA CENTRE
4	BADRI NARAYAN PRASAD	RDCIS, RANCHI
5	DHANANJAY GOVINDRAO NAOLAKHE	RDCIS, RANCHI
6	R.D. SHARMA	BHILAI STEEL PLANT, BHILAI.
7	S.C.D. GOEL	BHILAI STEEL PLANT, BHILAI.
8	S.K. GHOSH	BHILAI STEEL PLANT, BHILAI.
9	N. L. AGRAWAL	BHILAI STEEL PLANT, BHILAI.

PCT International Classification Number

C01B 17/74

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA